There have hitherto been contrived a variety of touch panels, in which, when a planar operation surface is touched by an operator with his or her finger and the like, a touched position and a pressed amount at the time of the touching are simultaneously detected.
For example, Patent Document 1 describes a touch input device having a structure such that a planar pressure-sensitive sensor and a touch panel for detecting a touched position are in close contact with and are superimposed each other. In this touch input device, the touched position is detected by the touch panel. The pressed amount is detected by the pressure-sensitive sensor formed separately from the touch panel and superimposed on the touch panel.    Patent Document 1: Japanese Patent Application Laid-Open No. 5-61592